Needle biopsy procedure, used to obtain tissue specimens for microscopic examination, is well known in most fields of medicine. Non-automatic, two hands-operated biopsy needle devices include a cutting needle in which a stylet slides in and out to save the tissue cut by the biopsy needle inside the stylet notch and the cutting needle lumen. The disadvantage of this biopsy procedure is the necessity to use two hands for handling the device, making this procedure more complicated and more prone to physicians' mistakes, such as needle movement and/or incorrect biopsy.
These disadvantages promoted the development of an automatic biopsy gun in which the movements of the cutting needle and the stylet are done by pressing buttons which actuate loaded springs. The springs drive the stylet and cutting needle forward sequentially, eliminating the need for two-handed operations. An example of an automatic biopsy gun is disclosed in Bates et al., U.S. Pat. No. 4,958,625. Such an automatic biopsy gun device is now the treatment of choice for core biopsies, such as per rectum prostate biopsy to detect malignancy. However, such a biopsy gun is lacking in at least two respects:
1. There is no effective protection for doctors or patients against accidental needle puncture during a procedure (especially in prostate core biopsies without trans-rectal ultrasonic guidance). The doctor may be exposed to cross-contamination and infections, and the patient may be exposed to rectal wall puncture and cross-contamination. PA1 2. Most patients require more than one needle biopsy to detect their pathology. The known manual and automatic guns are only capable of performing one biopsy per each insertion inside the body. After the biopsy is performed the steps are as follows: (A) the device is taken out of the body, (B) the device is opened by retracting the cutting needle proximally, (C) the biopsy is taken out, and (D) the biopsy gun can be loaded for a second biopsy. The length of time required for the procedure reflects the number of times the gun is introduced into the target body organ. When 10 to 12 prostate core biopsies are performed, the time of procedure is a multiple of the biopsies taken. Also, each needle puncture for getting to the target organ and obtaining a specimen increases trauma to the patient and/or site of the attempted biopsy.
A multi-biopsy gun is disclosed in U.S. Pat. No. 5,195,533, in which multiple biopsies are obtained in one body entrance puncture. According to the invention capturing multiple specimens in sequence without the need to unload each specimen is achieved by a double (or more) length of side notch stylet length and multiple gun loading and shooting once inside the target organ. According to the invention of the '533 patent, removal of the specimen is achieved by completely removing the cutting needle from the stylet notch area. The disadvantage of this device is that the gun must be loaded before each shooting. This loading, which is done while the needle is still inside the body tissue, is potentially dangerous since it requires the physician to apply force to the loaded gun which could cause accidental movement of the needle while inside the body tissue. If the gun is taken out of the body for a second loading and then reinserted into the body for a second biopsy, the advantage of single puncture multiple biopsy is negated. Thus, there would be great advantage to a single-insertion, multiple biopsy procedure without repeated spring loading inside the body.
An additional disadvantage of the multiple insertion biopsy gun of the '533 patent is the manner in which specimens are removed from the stylet notch. The biopsy gun of the '533 patent has a shooting step length of only one specimen length, and the only way to take out the second or more specimens is by moving the cutting needle forward and revealing the first or more specimen. This procedure is time consuming as well as potentially causing more damage to the first delicate tissue specimen when the long needle tube is retracted forward and creates friction with the specimen tissue.